There is known a processing device for processing an object by light radiated from a light emitting device. Examples of such a processing device include a laser exposure device for performing light exposure of a resist with laser light, and a laser machining device for machining, for example, cutting, an object with laser light.
The processing device includes a light emitting device and a driver circuit for driving the light emitting device. The driver circuit includes a switching device for current-control electrically connected to the light emitting device. The current flowing in the light emitting device is controlled by the switching device for current-control to control the intensity of light radiated from the light emitting device.
In such a driver circuit and a processing device, heat generation in the switching device for current-control causes a decrease of the lifetime of the switching device for current-control. In this regard, for instance, a cooling mechanism may be used to cool the switching device for current-control. However, providing a large-capacity cooling mechanism causes an increase in the size of the driver circuit and an increase in manufacturing cost. Thus, in the driver circuit and the processing device, it is desired to reduce the heat generation in the switching device for current-control with a simple configuration.